A group of Ontario farmers is claiming victory after Monsanto Co. agreed to sell its Posilac brand of synthetic cow hormones to drug maker Eli Lilly and Co. for $300 million.

Dave Mackay, president of the Renfrew County chapter of the National Farmers Union (NFU) and a former dairy farmer in Beachburg, Ont., told CBC News Friday that the sale is good news. Mackay, now a sheep farmer with a flock of 300, speaks for 150 farmers in Renfrew County.

"We think it's a bit of a victory," he said from his 200-acre farm near Pembroke, Ont. "We are pleased. I think we have won. Obviously, these guys are moving on."

Monsanto, an agricultural chemical company, announced the sale on Wednesday. It said the Posilac brand will become part of Lilly's Elanco animal health unit.

Posilac is the trade name of recombinant bovine somatotropin, or rBST, a hormone that increases milk production in cows. Monsanto has called it the leading dairy animal supplement in the U.S., with more than half a billion units used by dairy farmers since the product was approved for use in the U.S. in 1994.

Health Canada banned the use of rBST in 1998.

Mackay said he thinks Monsanto is getting out of the hormone business because of ongoing public opposition.

He said the NFU opposed the introduction of the hormone and took part in a national campaign, involving about 60 organizations, to convince the federal government to ban its use on Canadian dairy farms.

He said the campaign in the 1980s and 1990s raised public awareness of the dangers of rBST and helped convince Health Canada that it should not be used in this country.

The hormone, manufactured from genetically modified bacteria, is injected into dairy cows once or twice a month to boost their milk production. The increased production is said to cause cows to have a higher rate of illnesses, including mastitis, udder infections, and digestive problems.

Mackay said a group of NFU farmers travelled to the U.S. in the late 1990s to assess the health effects of the hormone on animal health. They interviewed farmers who use rBST on their herds.

"They said it burned the animals out," he said. "We think it affects the health of the cow, they don't breed back, it causes mastitis problems, the cows become disposable."

Mackay said on a recent trip to the U.S., he found that many farmers with small farms are no longer using the hormone because it is too hard on the cows but it is still popular on large farms with thousands of animals.

The NFU will continue to monitor the use of the hormone south of the border even though it is in the hands of Eli Lilly.

"We will keep an eye on them," Mackay said. "These guys have big money for lobbyists and scientists. They might try to reintroduce it [in Canada].

"They have a lot more money to spend than a bunch of farmers from Renfrew County."

With files from the Associated Press